Composing and Decomposing Numbers

Learning how to compose and decompose numbers is an essential skill that students learn from an early age. The rearranging parts strategy can be a useful tool for helping students in primary grades understand basic addition and subtraction. By breaking down a problem into smaller parts and rearranging those parts in different ways, students can better understand the underlying concepts and develop their problem-solving skills.

This worksheet displays two boxes of dots representing a number sentence. Students determine the initial number sentence by counting the dots in each box (the parts) and then figuring out the total (the whole). Once they have the total, they rearrange the parts in a different way to create a new number sentence with the same total to make ten.

An alternate version with the totals already filled in is provided to assist students who may have trouble understanding the concept.

Tips for Differentiation + Scaffolding  

In addition to individual student work time, use this worksheet as a:

• Lesson warm-up
• Lesson wrap-up
• Fast finishers 
• Homework assignment
• Whole-class review (via smartboard)

Expand this activity for students who are more capable by asking them to choose the easiest combination of numbers to add.

Encourage students who need additional help to use concrete materials such as counters to match the number of dots used in each question and then rearrange and record their answers.

Easily Download & Print

Use the dropdown icon on the Download button to choose between the PDF or editable Google Slides version of this resource. 

To save paper, we suggest printing this 2-page worksheet double-sided. 

Turn this teaching resource into a sustainable activity by printing on cardstock and slipping it into a dry-erase sleeve. Students can record their answers with a whiteboard marker, then erase and reuse them.

Additionally, project the worksheet onto a screen and work through it as a class by having students record their answers in their notebooks.

This resource was created by Kendall Britnell, a teacher in Colorado and Teach Starter Collaborator.